Unless you are a total minimalist, most travelers pack a smaller, secondary bag. These range from smaller daypacks to large purses. What you choose to bring will depend on your personal situation – like how many and which gadgets you bring with you and if you are traveling with anyone else.
If you are traveling with someone you can share packing duties, so even if you are bringing a larger, DSLR camera and laptop, you are probably only bringing one each, so it makes how many and which type of bag to bring easier. If you are traveling solo, you will have to make some tougher decisions on how much to bring since you only have yourself to rely on for carrying.
An extra backpack can be handy to use, depending on it’s size, for a day hike or as a city bag. When traveling on a bus or train, I throw my larger pack with my clothes and toiletries underneath and kept my small backpack with me at all times. It carried my expensive items – laptop, cameras, music, money and passport, etc.